Difficulty Order IYO?

How would you line up the following puzzles from easiest to hardest? (im getting into some harder puzzles and wonder what I should tackle first and how they line up with the ones I can already do! And ld love as many opinions as can gather!)

2x2 - 3x3 - 4x4 - 5x5 - 1x3x3 - Mirror Blocks 3x3 - Mirror Blocks 2x2 - Megaminx - Pyraminx - Skewb - Barrel 3x3 - Gear Cube (basic/original)